after each AJAX request completes to re-typeset any new math on the page.
I've included a piece of code that adds in this missing typeset call in a collection of small user script fixes that I'm calling the Stack Overflow Unofficial Patch.

Ps. Another similar issue (but with an unrelated cause) that I found while testing this is that, on the 10k flag review page, any math in posts hidden behind the "show posts you've already flagged" link is not typeset. The problem here is that the <div> containing the hidden posts has the class dno, which both makes it invisible and causes MathJax to ignore it, and the code that un-hides it just uses jQuery .show() on it without actually removing the class name. The Unofficial Patch linked above includes a fix for this issue too.